Apparatuses and methods of the aforementioned type are known in the art. For example, in application DE 10 2004 046 038 A1, a virtual operating room simulator is described that is intended in particular for training in endo-urological procedures. Contrary to surgical or endoscopic training models which make use of a realistic likeness of a body part or body cavity into which the tip of an endoscope is introduced to simulate a surgical or minimally invasive procedure, with a virtual simulator an image of a virtual environment, in particular of a body cavity, is generated with virtual reality methods and computer support and can be influenced interactively by the user. According to DE 10 2004 046 038 A1, the virtual operating room simulator includes a simulation computer unit to generate such a virtual endoscopic image in real time, an instrument whose proximal (that is, close to the user) part is a copy of the part of an endoscopically usable instrument, in particular a resectoscope, and an instrument insertion unit for inserting the instrument. In addition to displaying the virtual image, the force reaction onto the instrument or onto a distally positioned (that is, farther from the user) resection loop is computed and conveyed to the user. To record the movement of the instrument, incremental rotary encoders are provided in the instrument input unit and their signals are transmitted to a monitoring/control unit for further processing. The instrument also includes a carriage, which can be moved by the user in a manner that corresponds to the actuation of the resection loop. The movement of the carriage is transmitted by an axis to a linear potentiometer so that the position of the carriage can be picked up by a change in resistance.
In an article by Samur et al. (http://infoscience.epfl.ch/record/120548/files/Samur_HapticInterface_colonos copy_Haptics08.pdf), an apparatus is described for detecting movement and force recoupling in a colonoscopic simulation. Here, a colonoscope is introduced into an apparatus inside which rollers are friction-locked to the shaft of the colonoscope and convey a force reaction to the colonoscope. The movement of the rollers is measured by optical encoders to determine the linear and rotary movement of the shaft. Detecting the movement by means of rollers friction-locked to the shaft involves considerable technical complexity and inexactitude because of the necessary exact friction locking.
In WO 02/070980 A1, a simulation system for image-controlled medical methods is described in which a medical instrument, for example a catheter or endoscope, is introduced into an input unit inside which position encoders or sensors can be installed to follow the instrument's movements effected by the user. Possible sensors here include in particular two or four incremental position encoders or one or more optical sensors.
Manipulations of the internal body tissue are required as a rule in endoscopic procedures. Accordingly, flexible endoscopes usually comprise at least one working channel that runs inside the shaft that is insertable into a cavity and through which the one or more endoscopic working instruments can be introduced into the cavity. Such an endoscopic working instrument comprises an elongated shaft, which is provided for insertion into the working channel. In addition an endoscopic working instrument can comprise a tool that is positioned on the distal end of the shaft and configured to execute the desired manipulation. To actuate the tool, an actuation element can be provided on the proximal end of the shaft; by means of said element a user can control the movement of the working instrument and the tissue manipulation.
In an endoscopic simulation system it is therefore advantageous to be able also to provide training in actuating an endoscopic working instrument. For this purpose it is necessary to be able to record the movement of the working instrument, especially of the shaft, inside the working channel of the endoscope. The aforementioned arrangements, however, are not suited for detecting the movement of a flexible endoscopic working instrument inside a flexible endoscope.
In patent US 2005/0196739 A1 an endoscopic simulation system is disclosed that includes a training endoscope specially adapted for the simulation, as well as a detector that records the movements, controlled by the user, of the distal end of a flexible shaft of the training endoscope, an image-recording device that plots the shape of a patient's internal body cavity, and an image processor that generates a virtual three-dimensional image of the hollow organ from the acquired data. The training endoscope comprises an input through which an endoscopic working instrument can be introduced into the shaft of the training endoscope. In addition an element is provided to detect the movement of the inserted endoscopic working instrument. Said element comprises a calibrating or normalizing function. It thereby becomes possible to determine a starting point for introducing the endoscopic working instrument into the motion detection element that corresponds to a predetermined position inside the patient's body or inside the virtual organ. The functioning of the element to detect the movement of the working instrument is not described. There is no provision for detecting a rotary movement of the working element.